The present invention relates generally to an improved method and apparatus for removing entrained and dissolved gases from liquids and more specifically to an improved method and apparatus for deaerating solutions used in connection with artificial kidney dialysis machines and in connection with water purification systems such as reverse osmosis systems.
Although there are a variety of needs for solutions in which the dissolved gases have been removed, one of the primary uses for such a solution is in connection with artificial kidney dialysis machines. A frequent problem encountered by many hospitals in the northern United States and Canada arose because of the presence of dissolved gases in the cold water in these areas which was used in the preparation of the dialysate for use in artificial kidney units.
The dialysate is the physiological salt solution which passes through the dialyzer portion of the kidney unit and "rinses" wastes from the blood. The preparation of the dialysate includes heating the water to body temperature after which the warm solution flows through the dialyzer where the turbulence releases the dissolved gases. Because the dialysate still contained many dissolved gases, it was necessary to install a bubble catcher in the blood line between the dialyzer and the patient in order to trap air bubbles. However, such a bubble catcher had to be evacuated every five to ten minutes throughout the ten to fourteen hour dialysis treatment to prevent air emboli from entering the patient. This was an extremely difficult and demanding task which if not accomplished could be fatal to the patient. Consequently, there is an extreme need for an apparatus which would be able to efficiently and economically remove dissolved and entrained gases from solutions. In the past, other attempts at removing dissolved gases from solutions have included heating the solution and exposing the solution to ultrasonic energy. None of these attempts, however, have been successfully applied in the preparation of air free dialysate for use in kidney machines.
A second application for the present invention is in connection with water purification systems such as reverse osmosis systems which normally remove over 90% of the dissolved salts in a solution but which passes most of the dissolved gases. Also, many technical and industrial processes require a gas free solution since dissolved gases can interfere with mixing, upset flow and often impart unusual reactions.